The role of urinary neutrophil gelatinase-associated lipocalin in lupus nephritis

BACKGROUND

Urine neutrophil gelatinase-associated lipocalin (uNGAL) has been proposed as a potential biomarker for lupus nephritis (LN) activity. We determined the association between uNGAL with LN activity in systemic lupus erythematosus (SLE) patients compared to the current standard markers of SLE.

METHODS

A total of 100 SLE patients with biopsy-proven LN were recruited-47 with active and 53 inactive LN. uNGAL levels were measured. Renal function test, urinary parameters, lupus serology and calculated renal SLE Disease Activity Index-2K (renal SLEDAI-2K) were analyzed to determine their associations with uNGAL.

RESULTS

Normalized uNGAL levels (ng/mg creatinine) were significantly higher in patients with active LN compared to those with inactive disease (p=0.01). uNGAL and renal SLEDAI-2K were associated (r=0.32, p=0.001). Multiple logistic regression showed that only serum creatinine and renal SLEDAI-2K were independent predictors of uNGAL levels (p=0.03 and 0.02 respectively). Analysis of the receiver operating characteristic (ROC) curve showed that uNGAL was a potential biomarker for LN.

CONCLUSIONS

uNGAL was increased in active LN especially in LN flares. Serial measurements of uNGAL levels may be of value in monitoring response of LN to treatment and for predicting LN flares.

Serum neutrophil gelatinase-associated lipocalin and cystatin C are early biomarkers of contrast-induced nephropathy after coronary angiography in patients with chronic kidney disease

We had previously reported on serum neutrophil gelatinase-associated lipocalin (NGAL) as an earlier biomarker of contrast-induced nephropathy (CIN) than serum creatinine (SCr) in 100 patients with chronic kidney disease undergoing coronary angiography.(1) We then compared serum NGAL to serum cystatin C (CysC) in the same group of patients. The SCr, estimated glomerular filtration rate, serum NGAL, and serum CysC were measured at baseline and various time points as appropriate postprocedure. The frequency of CIN was 11% (n = 11). Serum NGAL increased ≥25% from baseline at 24 hours in 7 patients with CIN (P = .04). Serum CysC increased ≥25% from baseline at 24 hours in 4 patients with CIN (P = .008). Changes in serum NGAL and serum CysC from baseline at 24 hours (▵ values) could diagnose CIN 24 hours earlier than SCr with serum NGAL showing a superior performance.

Neutrophil Gelatinase-Associated Lipocalin as an Early Marker of Contrast-Induced Nephropathy After Coronary Angiography

We investigated whether serum neutrophil gelatinase-associated lipocalin (NGAL) was an early predictive biomarker of contrast-induced nephropathy (CIN) in patients with chronic kidney disease (n = 100) undergoing coronary catheterization. Serum creatinine (SCr) levels were measured at baseline, 24 hours, and 48 hours post procedure. Serum NGAL was measured preprocedure, 4 hours, and 24 hours post procedure. The frequency of CIN was 11%. In patients with CIN, SCr achieved significance only at 48 hours ( P = .006), whereas serum NGAL increased ≥25% from baseline at 24 hours in 7 of 11 patients with CIN ( P = .04) but did not change in the other 4. However, serum NGAL also rose ≥25% in 12 of 89 non-CIN patients. This subgroup could have had “incipient CIN.” Serum NGAL delta value at baseline, 24 hours was superior to SCr for early diagnosis of CIN. In conclusion, serum NGAL is an early predictive biomarker for CIN.